Technical Field
[0001] The present invention relates to a tire testing apparatus.
Background Art
[0002] A wear test of a tire for use in an automobile and the like is performed by multiplying
a force (ground contact force) applied to the tire and a slip amount of the tire by
each other to calculate wear energy. Then, heretofore, measurement of the ground contact
force has been performed, for example, by embedding a sensor for measuring the ground
contact force in a road surface. Moreover, the slip amount has been obtained by imaging
a ground contact surface of the tire and performing image processing therefor.
[0003] As such a conventional technology, for example, Patent Literature 1 described below
is present.
[0004] In Patent Literature 1, a camera and a transparent round bar are embedded in a road
surface, and a pressure sensor is installed around the round bar, whereby the measurement
of the ground contact force and the imaging of the ground contact surface of the tire
are performed.
Citation List
Patent Literature
Summary of Invention
Technical Problem
[0006] In Patent Literature 1, a part of an imaged image is modeled, and a range in which
the part is modeled is subjected to pattern matching, whereby a slip amount is specified.
However, there is a problem that it is difficult to set the range in which the part
is modeled while such range setting is manually performed by an operator or the like.
[0007] That is, when such a modeling range is set narrow, accuracy of the pattern matching
is reduced since the number of feature portions in the image is small. Meanwhile,
when the modeling range is set wide, there is a problem that the pattern matching
cannot be performed since the range extends off the imaged image. Particularly in
the case of a drum-type tire testing apparatus that images a tire while bringing the
tire into contact with a drum and rotating the tire, there is a problem that processing
for the pattern matching is difficult since an imaging position of the tire moves
following the rotation of the drum.
[0008] Another device known from
CN 108 225 798 comprises a tire slip amount test system that detects the slip amount based on the
displacement of marking points that are physically sprayed on selected positions of
the tire tread. It has a test platform provided with a glass table plate that is arranged
in a frame.
[0009] The frame is connected with a tire that is connected with a rolling control mechanism.
A side wall of the frame is provided with a laser corresponding to the front and rear
of tire rolling direction. A circle of a LED illumination lamp is arranged in the
glass table plate to surround a contact surface of the tire and the glass table plate.
A camera is arranged in the contact surface of the tire and the glass table plate.
A workstation is connected with the LED illumination lamp. The camera data receives
image data and processes a data display.
Solution to Problem
[0011] In this connection, the inventor of the present invention has invented a tire testing
apparatus of the present invention in view of the above-described problems.
[0012] A first invention is a tire testing apparatus of a drum type according to claim 1.
[0013] By using the present invention, division processing at the time of performing such
image information matching processing for calculating the slip amount can be set automatically
and appropriately.
[0014] In the above-mentioned invention, the division processing unit can be configured
like a tire testing apparatus that divides the image information subjected to the
edging processing into regions with a predetermined size, and in each of the divided
regions, performs processing for repeating the division of the region until the number
of bright spot pixels in the region becomes less than a predetermined threshold value.
[0015] The matching processing is performed by using the edged image information. Therefore,
when the number of bright spot pixels does not satisfy a predetermined condition regarding
the bright spot pixels, for example, is a predetermined threshold value or more, then
a desired resolution is not obtained. Therefore, in order to obtain the desired resolution,
it is preferable to repeat the division of the regions until the bright spot pixels
satisfy the predetermined condition.
[0016] In the above-mentioned invention, the matching processing unit can be configured
like a tire testing apparatus that performs matching processing for matching the divided
region and image information of the ground contact surface of the tire with each other,
the image information being subjected to the edging processing at different time from
the divided region.
[0017] By the present invention, slips from a tread start to a kickout can be matched in
a time series, and accordingly, an influence of a tire curvature radius is less liable
to be given, and a calculation error of the slip amount can be reduced.
[0018] In the above-mentioned invention, the slip amount calculation processing unit can
be configured like a tire testing apparatus that: computes a coordinate of a point
at a predetermined position in the divided region and a coordinate of a corresponding
point in the matched region and thereby calculates a displacement; and calculates
the slip amount by using the calculated displacement.
[0019] A computer program of the present invention according to claim 4 is disclosed.
Advantageous Effects of Invention
[0020] By using the tire testing apparatus of the present invention, the range in which
such image pattern matching for calculating the slip amount of the tire can be set
automatically and appropriately.
Brief Description of Drawings
[0021]
Fig. 1 is a view illustrating a whole of an example of a tire testing apparatus of
the present invention.
Fig. 2 is an enlarged view of a vicinity of a sensor installation portion of the tire
testing apparatus of the present invention.
Figs. 3(a) and 3(b) are longitudinal cross-sectional and top plan views of the tire
testing apparatus of the present invention.
Figs. 4(a) and 4(b) are views schematically illustrating states in which imaging by
an imaging device and measurement of a ground contact force by a sensor are performed
in the tire testing apparatus of the present invention.
Fig. 5 is a diagram schematically illustrating an example of hardware of a control
computer of the tire testing apparatus of the present invention.
Fig. 6 is a block diagram schematically illustrating an example of a processing function
in the control computer.
Fig. 7 is a flowchart illustrating an example of a processing process in the tire
testing apparatus of the present invention.
Figs 8(a) and 8(b) are views schematically illustrating a state of imaging a ground
contact surface of a tire and image information obtained thereby, the information
being regarding the ground contact surface of the tire at every angle θT of a tire shaft.
Fig. 9 is a view illustrating an example of the image information of the ground contact
surface of the tire.
Fig. 10 is a view illustrating an example of image information in which the image
of Fig. 9 is subjected to gray-scale conversion.
Fig. 11 is a view illustrating an example of edged image information.
Fig. 12 is a view schematically illustrating processing for dividing the edged image
information of the ground contact surface of the tire into regions with a predetermined
size.
Fig. 13 is a view schematically illustrating processing for dividing the regions on
the basis of the number of bright spot pixels.
Fig. 14 is a view schematically illustrating a template and a center coordinate thereof.
Fig. 15 is a view schematically illustrating processing for performing matching processing
between edged image information of the ground contact surface of the tire at different
time and image information of the template and specifying a center coordinate of a
corresponding region.
Fig. 16 is a view illustrating a state in which a slip amount is displayed to be superimposed
on the edged image information of the ground contact surface of the tire.
Description of Embodiments
[0022] An example of an exterior appearance of a tire testing apparatus 1 of the present
invention is illustrated in Fig. 1. Moreover, an enlarged view of a vicinity of a
sensor installation portion for performing measurement of a ground contact force,
the sensor installation portion going to be described later, is illustrated in Fig.
2.
[0023] The tire testing apparatus 1 is a drum-type testing apparatus for measuring a ground
contact force of a tire 5 and imaging a ground contact surface of the tire 5. The
tire testing apparatus 1 performs a test by bringing the tire 5 as a test target into
ground contact with an outer circumferential surface (drum surface) of a drum 10 that
rotates about a drum shaft 13. A part of the drum surface is provided with: the sensor
installation portion including a sensor for measuring a ground contact force of the
tire 5; and a transmission portion 11 for performing imaging by an imaging device
14.
[0024] In such a sensor installation portion 12, a plurality of, for example, approximately
eighty 3-component force sensors 12a (sensors 12a which measure forces in the respective
directions of an X-axis, a Y-axis and a Z-axis) are installed in a width direction
of the drum surface. The drum 10 rotates about the drum shaft 13, whereby a surface
(ground contact surface) of the tire 5 is brought into ground contact with the sensors
12a of the sensor installation portion 12, and the measurement of the ground contact
force of the tire 5 is thereby performed. As the 3-component force sensors 12a, for
example, Force Matrix Sensors (FMSs) manufactured by the applicant can be used.
[0025] It is preferable that, in the transmission portion 11, a portion from an inside of
the drum 10 to an outside thereof be composed of a transparent material so that the
imaging device 14 is capable of imaging the ground contact surface of the tire 5,
which is brought into ground contact with the transmission portion 11. For example,
reinforced glass, reinforced plastics and the like are mentioned; however, the transmission
portion 11 is not limited to these. Moreover, regarding a friction coefficient of
the transmission portion 11, it is preferable to use a material with a friction coefficient
same as or approximate to that of the drum surface.
[0026] In an inside of a housing of the drum 10, the imaging device 14 that images the ground
contact surface of the tire 5 via the transmission portion 11 is provided. Preferably,
a lens of the imaging device 14 is fixed in advance onto a diameter, which connects
the drum shaft 13 and the transmission portion 11 to each other, so as to be directed
toward the transmission portion 11, and a tire surface of the tire, which is brought
into ground contact with the transmission portion 11, is imaged from the inside of
the housing of the drum 10 via the transmission portion 11. However, such a configuration
can also be adopted so that a reflecting member such as a mirror is provided in the
inside of the housing of the drum 10, and that the imaging device 14 images the ground
contact surface of the tire 5 via the reflecting member and the transmission portion
11.
[0027] The tire testing apparatus 1 includes a tire support mechanism that supports the
tire 5 freely rotatably about the tire shaft 51, and moves the tire support mechanism
back and forth with respect to the drum 10, thus making it possible to perform a control
to bring the tire 5 into ground contact with the outer circumferential surface of
the drum 10 and to separate the tire 5 therefrom. Moreover, in the tire testing apparatus
1, the drum 10 or the tire 5 is controlled to be movable in a relatively transverse
direction with respect to a direction of a rotation shaft of the drum 10.
[0028] In the drum shaft 13 for rotating the drum 10 and the tire shaft 51 for rotating
the tire 5, angle encoders (rotary encoders) are individually provided, and individually
measure angles (angle θ
D by which the drum 10 rotates from a reference point and angle θ
T by which the tire 5 rotates from the reference point) from the reference point. Note
that any method other than the angles may be adopted if rotational positions from
the reference point can be detected thereby.
[0029] The tire testing apparatus 1 includes a control computer 7 that performs a control
thereof. The control computer 7 includes: a computing device 70 such as a CPU, which
executes computing processing for a program; a storage device 71 such as a RAM and
a hard disk, which stores information; a display device 73 such as a display, which
displays information; an input device 72 such as a keyboard and a mouse, which is
capable of inputting information; and a communication device 74 that transmits and
receives a processing result of the computing device 70 and the information, which
is stored in the storage device 71, via a network such as the Internet and a LAN.
[0030] When the computer is provided with a touch panel display, the display device 73 and
the input device 72 may be composed integrally with each other. The touch panel display
is often used, for example, for a portable communication terminal such as a tablet
computer and a smartphone, but is not limited to this.
[0031] The touch panel display is a device in which functions of the display device 73 and
the input device 72 are integrated with each other in that an input can be directly
performed on a display thereof by a predetermined input device (pen for a touch panel),
a finger and the like.
[0032] An arrangement relationship between the sensors 12a of the sensor installation portion
12, which are provided on the drum surface of the tire testing apparatus 1, and the
transmission portion 11 is fixed. An angle (angle from the reference point) of the
tire shaft 51 when the tire 5 is brought into ground contact with the drum 10 is defined
as θ
0(θ
T=θ
0), and an angle (angle from the reference point) of the drum shaft 13, at which the
imaging device 14 is capable of imaging the ground contact surface of the tire 5 via
the transmission portion 11, is defined as θ
1(θ
D=θ
1). Moreover, an angle (angle from the reference point) of the drum shaft 13 when the
ground contact surface of the tire 5, which serves as an imaging target, is brought
into ground contact with the sensors 12a of the sensor installation portion 12, is
defined as θ
2(θ
D=θ
2). Regarding the drum shaft 13 of the tire testing apparatus 1 and the tire shaft
51, the control computer 7 controls rotations of the respective shafts so that timing
when θ
T=θ
0 and θ
D=θ
1 is established and timing when θ
T=θ
0 and θ
D=θ
2 is established are generated (synchronized). It is Figs. 4(a) and 4(b) that schematically
illustrate this. For example, when a reference point A is present on an extension
of respective centers of the drum shaft 13 and the tire shaft 51 as illustrated in
Figs. 4(a) and 4(b), θ
T = 180 degrees (θ
0=180), θ
D = 0 degree (θ
1 = 0), and θ
D = 270 degrees (θ
2=270) are established. Then, the ground contact surface of the tire 5, which is imaged
by the imaging device 14 via the transmission portion 11 at the time of θ
T = 180 degrees and θ
D = 0 degree and the ground contact force measured by the sensors 12a of the sensor
installation portion 12 at the time of θ
T = 180 degrees and θ
D = 270 degrees become information for the same ground contact surface of the tire
5. Note that, in Figs. 4(a) and 4(b), the case in which the reference point of the
angle θ
D of the drum shaft 13 and the reference point of the angle θ
T of the tire shaft 51 are the same is illustrated; however, points different from
each other may be used as such reference points.
[0033] In general, a radius of the drum 10 and a radius of the tire 5 do not coincide with
each other. Accordingly, to control rotation speeds of the drum shaft 13 and the tire
shaft 51 as mentioned above is present as one of methods for synchronizing the drum
10 and the tire 5 with each other.
[0034] Moreover, as another method for synchronizing the drum 10 and the tire 5 with each
other, the rotation speeds themselves of the drum shaft 13 and the tire shaft 51 are
not controlled, but such a method as follows is present. While rotating the drum shaft
13 and the tire shaft 51 at an arbitrary number of revolutions (number of revolutions
may be fixed or variable), the measurement by the sensors 12a of the sensor installation
portion 12 and the imaging of the ground contact surface of the tire 5 using the imaging
device 14 are performed in advance. Then, the angle θ
T of the tire shaft 51, the angle θ
D of the drum shaft 13 and the ground contact force measured by the sensors 12a at
a point of measurement time and the angle θ
T of the tire shaft 51, the angle θ
D of the drum shaft 13 and the imaged image information at the point of measurement
time are stored in association with each other. Then, a ground contact force and image
information regarding a ground contact surface of a certain tire 5 can also be obtained
by being specified on the basis of an angle θ
T of a tire shaft 51 of the ground contact surface of the tire 5 taken as such a processing
target and an angle θ
D of the drum shaft 13, which corresponds thereto.
[0035] That is, timing when the angle θ
T of the tire shaft 51 when the ground contact surface of the tire 5 taken as a processing
target is brought into ground contact with the sensors 12a of the sensor installation
portion 12 and the transmission portion 11 becomes θ
0 is specified, and moreover, timing when the angle θ
D of the drum shaft 13 when the tire 5 is brought into ground contact with the transmission
portion 11 of the drum 10 becomes θ
1 is specified. Likewise, timing when the angle θ
D of the drum shaft 13 when the tire 5 is brought into ground contact with the sensors
12a in the sensor installation portion 12 of the drum 10 becomes θ
2 is specified. Then, the drum shaft 13 and the tire shaft 51 are rotated for a predetermined
time, whereby the image information of the ground contact surface of the tire 5 and
the ground contact force of the tire 5 when 0 degree ≤ θ
T ≤ 360 degrees is established for the tire shaft 51 and 0 degree ≤ θ
D ≤ 360 degrees is established for the drum shaft 13 are individually acquired and
measured in advance. Then, when there gather a predetermined threshold value or more
(for example, 98% or more) of data of the respective items, image information of the
ground contact surface of the tire 5, which is imaged via the transmission portion
11 by the imaging device 14 at the time of θ
T=180 degrees and θ
D = 0 degrees, and a ground contact force measured by the sensors 12a of the sensor
installation portion 12 at the time of θ
T=180 degrees and θ
D=270 degrees are associated with each other.
[0036] In Fig. 6, an example of a processing function in the control computer 7 is schematically
illustrated in a block diagram. The computing device 70 of the control computer 7
includes a ground contact force measurement processing unit 700, a ground contact
surface imaging processing unit 701, an edging processing unit 702, a division processing
unit 703, a matching processing unit 704, a slip amount calculation processing unit
705, a wear energy calculation processing unit 706. Note that, though a case of achieving
the above-mentioned respective processing functions in the control computer 7 that
controls the tire testing apparatus 1 is described in this description, the above-described
respective processing functions may be achieved by another computer than the control
computer 7 that controls the tire testing apparatus 1.
[0037] The ground contact force measurement processing unit 700 measures values of the sensors
12a, which are measured by the sensors 12a of the sensor installation portion 12 installed
on the drum surface, the angle θ
T of the tire shaft 51 from the reference point at that time, and the angle θ
D of the drum shaft 13 from the reference point at that time. The measured values of
the sensors 12a and the angle θ
T of the tire shaft 51 and the angle θ
D of the drum shaft 13 at that time and a time t are stored in the storage device 71
in association with one another.
[0038] By using the imaging device 14, the ground contact surface imaging processing unit
701 images the ground contact surface of the tire 5, which is brought into ground
contact with the transmission portion 11, via the transmission portion 11 installed
on the drum surface. Since the imaging device 14 images the ground contact surface
of the tire 5 via the transmission portion 11, the ground contact surface of the tire
5 is imaged via the transmission portion 11 by the imaging device 14 when the angle
of the drum shaft 13 is an angle θ
1(θ
D=θ
1) at which the imaging via the transmission portion 11 is possible. Moreover, the
imaging device 14 not only performs the imaging when the angle of the drum shaft 13
is θ
1, but also may always perform the imaging in advance, associate the angle θ
D of the drum shaft 13 and the angle θ
T of the tire shaft 51 at that time with each other, and extract image information
when the angle of the drum shaft 13 is θ
1.
[0039] Preferably, the ground contact surface imaging processing unit 701 images a ground
contact surface of an entire circumference (0 degree ≤ θ
T ≤ 360 degrees as the angle of the tire shaft 51) of the tire 5. The image information
of the imaged tire surface is stored in the storage device 71 in association with
the time t and the angle θ
T of the tire shaft 51.
[0040] The edging processing unit 702 executes edging processing for detecting an edge of
the image information imaged by the ground contact surface imaging processing unit
701. Such edge detection processing is processing for detecting an outline included
in the image information, and includes a variety of known methods. For example, changes
(gradients) of respective pixel values of the image information are calculated by
differentiation and the like, whereby the edge can be detected. In the present invention,
since the ground contact surface of the tire 5 is imaged, an outline (tread pattern)
of the ground contact surface of the tire 5 will be detected.
[0041] The division processing unit 703 divides image information on a certain ground contact
surface (angle of a certain tire shaft 51), the image information being edged by the
edging processing unit 702, into regions with a predetermined size. Then, when the
number of bright spot pixels in each of the regions is a predetermined threshold value
or more, the division processing unit 703 further divides the region. It is preferable
that the division processing unit 703 divide the region into two; however, no limitations
are imposed thereon. Note that the division processing unit 703 does not divide the
region if the number of bright spot pixels in the region is less than the predetermined
threshold value. The division processing unit 703 repeats the division of the regions
until the number of bright spot pixels in the region becomes less than the predetermined
threshold value. The division of the region, which is based on the number of bright
spot pixels, is performed for matching processing by a desired resolution. Accordingly,
if the division of the region is such division processing that the desired resolution
is obtained, then a determination may be made on the basis of a criterion other than
the bright spot pixels, for example, a ratio of the bright spot pixels and pixels
other than the same. Moreover, even in the case of using the number of bright spot
pixels, the processing may be other than such a comparison between the number of pixels
and the threshold value.
[0042] The matching processing unit 704 adopts, as a template, one of the regions divided
by the division processing unit 703, and acquires a center coordinate thereof. Moreover,
the matching processing unit 704 performs matching processing for image information
edged at different time and the region of the template with each other, specifies
a corresponding region (for example, a region with highest similarity), and acquires
a center coordinate thereof. The matching processing unit 704 executes the matching
processing in a necessary region and an angle (ground contact surface of the tire
5) of the tire shaft 51.
[0043] The slip amount calculation processing unit 705 computes a difference between the
center coordinate of the template and the center coordinate of the region specified
as a result of the matching processing in each region and each angle of the tire shaft
51. Moreover, the slip amount calculation processing unit 705 further subtracts a
longitudinal ground contact surface moving amount (= time (differential time Δt from
such an image adopted as the template at the time of the matching processing) × speed),
which is generated by the rotation of the drum 10, from a computing result of the
above-described difference. By accumulating such results as calculated, the slip amount
is calculated.
[0044] The wear energy calculation processing unit 706 associates the ground contact force
measured by the ground contact force measurement processing unit 700 and the slip
amount calculated by the slip amount calculation processing unit 705 with each other,
and computes these, for example, multiplies these by each other, thereby calculating
wear energy.
[0045] Next, an example of a processing process of the tire testing apparatus 1 of the present
invention will be described with reference to a flowchart of Fig. 7.
[0046] First, in the tire testing apparatus 1, the tire 5 taken as a processing target is
attached to the tire shaft 51, and then the tire 5 is rotated about the tire shaft
51 with a predetermined load and at a predetermined speed. Thus, the ground contact
force measurement processing unit 700 measures the values of the sensors 12a, which
are measured by the sensors 12a of the sensor installation portion 12 installed on
the drum surface, the angle θ
T of the tire shaft 51 from the reference point at that time, and the angle θ
D of the drum shaft 13 from the reference point at that time, and allows storage of
the measured values of the sensors 12a and the angles θ
T and θ
D in association with the time t.
[0047] Moreover, simultaneously, the ground contact surface imaging processing unit 701
images the tire 5, which is brought into ground contact with the transmission portion
11, via the transmission portion 11 installed on the drum surface, thereby acquiring
the image information of the ground contact surface of the entire circumference or
part of the tire 5 (S100). The ground contact surface imaging processing unit 701
associates the angle θ
T of the tire shaft 51 and the angle θ
D of the drum shaft 13 at that time and the time t with the imaged image information,
and causes the storage device 71 to store the image information. It is Figs. 8(a)
and 8(b) that schematically illustrates this. Fig 8(a) is a view schematically illustrating
a state of imaging the ground contact surface of the tire 5, and Fig. 8(b) is a view
illustrating image information obtained thereby, the image information being regarding
the ground contact surface of the tire 5 at every angle θ
T of the tire shaft 51. Moreover, an example of the image information of the ground
contact surface of the tire 5 is illustrated in Fig. 9.
[0048] When the image information of the ground contact surface of the tire 5 is acquired
as described above, the edging processing unit 702 performs gray-scale conversion
for each of the image information, and performs the edging processing for the image
information subjected to the gray-scale conversion (S110). The image information obtained
by performing the gray-scale conversion for the image information of the ground contact
surface of the tire 5 in Fig. 9 is illustrated in Fig. 10. Moreover, such image information
thus edged is illustrated in Fig. 11.
[0049] After the edging processing in the edging processing unit 702, the division processing
unit 703 divides the image information on the ground contact surface (angle of the
tire shaft 51, which corresponds to the ground contact surface taken as a processing
target) taken as a processing target, the image information having been edged by the
edging processing unit 702, into regions with a predetermined size (S120). It is Fig.
12 that schematically illustrates this. Then, when the number of bright spot pixels
in each of the regions satisfies a predetermined condition, for example, is a predetermined
threshold value or more, the division processing unit 703 further divides the region,
and repeats the division of the regions until the number of bright spot pixels in
a region thus already divided becomes less than the predetermined threshold value
(S130). It is Fig. 13 that schematically illustrates this.
[0050] When the region is divided until the number of bright spot pixels becomes less than
the predetermined threshold value as described above, the matching processing unit
704 adopts one of such regions as a template, and acquires a center coordinate (X1,
Y1) thereof (S140). It is Fig. 14 that schematically illustrates this.
[0051] Moreover, regarding the image information (image information at the time t) divided
in S120, the matching processing unit 704 performs matching processing for image information
edged at different time (time t+Δt) from the image information (image information
at the time t) divided in S120, and the image in the region of the template with each
other, specifies a corresponding region (for example, a region with highest similarity),
and acquire a center coordinate (X2, Y2) thereof (S150). At this time, as a range
to be subjected to the matching processing, only a peripheral fixed range of the region
that composes the template (that is, a range composed of coordinates of the template
in the image information edged at the time t) is recommended to be subjected to be
the matching processing. This is because, since many similar surfaces are included
in the ground contact surface of the tire 5, accuracy of the matching processing can
be improved in such a manner that the range to be subjected to the matching processing
is limited to such a fixed range. It is Fig. 15 that schematically illustrates this.
Then, the storage device 71 is caused to store a correspondence relationship between
the center coordinate (X1, Y1) of the template and the center coordinate (X2, Y2).
[0052] The above processing is executed for all the regions of the image information in
the ground contact surface (angle of the tire shaft 51) of the tire 5, for which the
slip amount is required to be calculated (S160, S170).
[0053] Then, when such correspondence relationships between the center coordinate (X1, Y1)
of the template and the center coordinate (X2, Y2) are specified for all the regions
and all the angles of the tire shaft 51, for which such slip amounts are required
to be calculated, the slip amount calculation processing unit 705 calculates a displacement
of the center coordinate on the basis of the correspondence relationship (S180). That
is, the slip amount calculation processing unit 705 computes a difference of the center
coordinate (X2, Y2) from the center coordinate (X1, Y1), and calculates the displacement.
At this time, the slip amount calculation processing unit 705 further subtracts the
longitudinal ground contact surface moving amount (= time (Δt) × speed), which is
generated by the rotation of the drum 10, from the computing result of the above-described
difference (S190). By accumulating such results as calculated, the slip amount is
calculated. The slip amount calculated as described above is displayed to be superimposed
on the edged image information (Fig. 11) at the time t. The slip amount is recommended
to be displayed so as to be visually distinguishable from one another by arrows having
lengths, thicknesses, colors or the like, each of which corresponds to the slip amount.
It is Fig. 16 that schematically illustrates this.
[0054] When the slip amount on the ground contact surface (angle θ
T of the tire shaft 51) of the tire 5 taken as a processing target is calculated as
described above, the wear energy calculation processing unit 706 extracts the ground
contact force, which corresponds to the angle θ
T of the tire shaft 51, from the storage unit, computes these, and calculates wear
energy.
[0055] Such processing as described above is executed, whereby the region at the time of
performing the matching processing for calculating the slip amount can be set automatically,
and accordingly, a load applied to the matching processing can also be reduced.
Industrial Applicability
[0056] By using the tire testing apparatus 1 of the present invention, the range in which
such image pattern matching for calculating the slip amount of the tire 5 can be set
automatically and appropriately.
Reference Signs List
[0057]
- 1
- tire testing apparatus
- 5
- tire
- 7
- control computer
- 10
- drum
- 11
- transmission portion
- 12
- sensor installation portion
- 12a
- sensor
- 13
- drum shaft
- 14
- imaging device
- 51
- tire shaft
- 70
- computing device
- 71
- storage device
- 72
- input device
- 73
- display device
- 74
- communication device
- 700
- ground contact force measurement processing unit
- 701
- ground contact surface imaging processing unit
- 702
- edging processing unit
- 703
- division processing unit
- 704
- matching processing unit
- 705
- slip amount calculation processing unit
- 706
- wear energy calculation processing unit
1. Reifentestgerät (1) vom Trommeltyp, umfassend:
eine Trommel (10) mit einem Übertragungsabschnitt (11) an einer äußeren Umfangsfläche
eine Abbildungsvorrichtung (14), die eine Bodenkontaktfläche eines Reifens (5) von
einer Innenseite der Trommel (10) über den Übertragungsabschnitt (11) abbildet, wobei
der Reifen (5) an einer Reifenwelle (51) befestigt ist;
eine Bodenkontaktflächen-Abbildungsverarbeitungseinheit (701), die unter Verwendung
der Abbildungsvorrichtung (14) die Bodenkontaktfläche abbildet, wenn der Reifen (5)
in Bodenkontakt mit dem Übertragungsabschnitt (11) gebracht wird, wodurch Bildinformationen
der Bodenkontaktfläche des gesamten Umfangs oder eines Teils des Reifens (5) erfasst
werden, wobei die Bildinformationen die abgebildete Bodenkontaktfläche des Reifens
in jedem Winkel θT der Reifenwelle (51) sind;
eine Kantenverarbeitungseinheit (702), die eine Kantenverarbeitung der Bildinformationen
der abgebildeten Bodenkontaktfläche des Reifens (5) durchführt;
eine Teilungsverarbeitungseinheit (703), die eine Teilungsverarbeitung der Bildinformation,
die der Kantenverarbeitung unterzogen wurde, in Bereiche durchführt, die eine vorbestimmte
Auflösungsbedingung erfüllen;
eine Anpassungsverarbeitungseinheit (704), die eine Anpassungsverarbeitung unter Verwendung
der unterteilten Bereiche durchführt,
wobei die Anpassungsverarbeitungseinheit (704) einen der durch die Teilungsverarbeitungseinheit
(703) geteilten Bereiche als eine Schablone annimmt und eine Anpassungsverarbeitung
zum Anpassen des Bereichs der Schablone und der Bildinformation der Bodenkontaktoberfläche
des Reifens (5) aneinander durchführt, wobei die Bildinformation, die angepasst wird,
der Kantenverarbeitung zu einer anderen Zeit als dem geteilten Bereich der Schablone
unterzogen wird; und
eine Schlupfbetragsberechnungs-Verarbeitungseinheit (705), die einen Schlupfbetrag
unter Verwendung eines Ergebnisses der Anpassungsverarbeitung und eines durch einen
Rotationsbetrag der Trommel (10) erzeugten Bodenkontaktflächen-Bewegungsbetrags berechnet,
wobei der Bewegungsbetrag der Bodenkontaktfläche eine Differenzzeit multipliziert
mit einer Geschwindigkeit der Trommel (10) darstellt.
2. Reifentestgerät (1) nach Anspruch 1,
wobei die Teilungsverarbeitungseinheit (703):
die Bildinformation, die der Kantenverarbeitung unterzogen wird, in Bereiche mit einer
vorbestimmten Größe unterteilt; und
in jedem der unterteilten Bereiche eine Verarbeitung zum Wiederholen der Unterteilung
des Bereichs durchführt, bis eine Anzahl von hellen Fleckenpixeln in dem Bereich kleiner
als ein vorbestimmter Schwellenwert wird.
3. Reifentestgerät (1) nach Anspruch 1 oder 2,
wobei die Schlupfbetragsberechnungs-Verarbeitungseinheit (705):
eine Koordinate eines Punktes an einer vorbestimmten Position in dem geteilten Bereich
und eine Koordinate eines entsprechenden Punktes in dem angepassten Bereich berechnet
und dadurch eine Verschiebung berechnet; und
Berechnen des Schlupfbetrags unter Verwendung der berechneten Verschiebung.
4. Computerprogramm, das Anweisungen enthält, die, wenn das Programm von einem Computer
ausgeführt wird, den Computer veranlassen, wie folgt zu funktionieren:
eine Bodenkontaktoberflächen-Abbildungsverarbeitungseinheit (701), die unter Verwendung
einer Abbildungsvorrichtung (14) eine Bodenkontaktoberfläche abbildet, wenn ein Reifen
(5) in Bodenkontakt mit einem Übertragungsabschnitt (11) einer Trommel (10) gebracht
wird, wodurch Bildinformationen der Bodenkontaktoberfläche des gesamten Umfangs oder
eines Teils des Reifens (5) erfasst werden,
wobei die Bildinformation die abgebildete Bodenkontaktfläche des Reifens bei jedem
Winkel θT einer Reifenwelle (51) ist;
die Abbildungsvorrichtung (14) die Bodenkontaktfläche des Reifens (5) von der Innenseite
der Trommel (10) über den Übertragungsabschnitt (11) abbildet, der an einer äußeren
Umfangsfläche der Trommel (10) vorgesehen ist, wobei der Reifen (5) an der Reifenwelle
(51) befestigt ist;
eine Kantenverarbeitungseinheit (702), die eine Kantenverarbeitung der Bildinformation
der abgebildeten Bodenkontaktfläche des Reifens (5) durchführt;
eine Teilungsverarbeitungseinheit (703), die eine Teilungsverarbeitung der Bildinformation,
die der Kantenverarbeitung unterzogen wurde, in Bereiche durchführt, die eine vorbestimmte
Auflösungsbedingung erfüllen;
eine Anpassungsverarbeitungseinheit (704), die eine Anpassungsverarbeitung unter Verwendung
der unterteilten Bereiche durchführt,
wobei die Anpassungsverarbeitungseinheit (704) einen der durch die Teilungsverarbeitungseinheit
(703) geteilten Bereiche als eine Schablone annimmt und eine Anpassungsverarbeitung
zum Anpassen des Bereichs der Schablone und der Bildinformation der Bodenkontaktfläche
des Reifens (5) aneinander durchführt, wobei die Bildinformation, die angepasst wird,
der Kantenverarbeitung zu einer anderen Zeit als der geteilte Bereich der Schablone
unterzogen wird; und
eine Schlupfbetragsberechnungs-Verarbeitungseinheit (705), die einen Schlupfbetrag
unter Verwendung eines Ergebnisses der Anpassungsverarbeitung und eines durch einen
Rotationsbetrag der Trommel (10) erzeugten Bodenkontaktflächen-Bewegungsbetrags berechnet,
wobei der Bewegungsbetrag der Bodenkontaktfläche eine Differenzzeit multipliziert
mit einer Geschwindigkeit der Trommel (10) darstellt.